Introduction

This ATSB booklet aims to increase awareness among flying instructors and pilots of the issues relating to partial power loss after takeoff in single-engine aircraft. Accident investigations have shown that a significant number of occurrences result in fatalities or serious injury due to the aircraft stalling and subsequent loss of control resulting in a collision with the ground or water.

Historically, the simulated total loss of power and subsequent practice forced landing has been the core of a pilot’s emergency training. The data, however, shows that during and after takeoff, a partial power loss is three times more likely in today’s light single-engine aircraft than a complete engine failure. Furthermore, there have been nine fatal accidents from 2000 to 2010 as a result of a response to a partial power loss compared with no fatal accidents where the engine failed completely.

While one reason for the disparity in these statistics could be the more challenging nature of partial power loss, due to the choices confronting a pilot and the decisions that have to be made immediately, it does not fully explain the different outcomes. Another possible factor is training. Total engine failure after takeoff is part of the Day VFR syllabus and is taught and practiced throughout a pilot’s initial training. However, partial power loss after takeoff is not a specific syllabus item, and probably does not receive the same emphasis during training.

While acknowledging the difficulty of attempting to train pilots for a partial power loss event which has an almost infinite variability of residual power and reliability, analysis of the occurrences supports the need to raise greater awareness of the hazards associated with partial power loss and to better train pilots for this eventuality.

Partial engine power loss is more complex and more frequent than a complete engine power loss.

Key messages

Most fatal and serious injury accidents resulting from partial power loss after takeoff are avoidable. This booklet will show that you can prevent or significantly minimise the risk of bodily harm following a partial or complete engine power loss after takeoff by using the strategies below:

pre-flight decision making and planning for emergencies and abnormal situations for the particular aerodrome

conducting a thorough pre-flight and engine ground run to reduce the risk of a partial power loss occurring

taking positive action and maintaining aircraft control either when turning back to the aerodrome or conducting a forced landing until on the ground, while being aware of flare energy and aircraft stall speeds.

Summary

Pre-flight checks prevent partial power loss

ATSB occurrence statistics indicate that many partial power losses could have been prevented by thorough pre-flight checks. Some conditions reported as causing partial power loss after takeoff are fuel starvation, spark plug fouling, carburettor icing and pre-ignition conditions. In many cases, these conditions may have been identified throughout the pre-takeoff and on-takeoff check phases of the flight sequence.

Pre-flight planning and pre-takeoff briefings

Even if a partial power loss does occur after takeoff, considering actions to take following a partial power loss after takeoff during the process of planning and the pre-flight safety brief gives pilots a much better chance of maintaining control of the aircraft, and helps the pilot respond immediately and stay ahead of the aircraft. Considerations include planning for rejecting a takeoff, landing immediately within the aerodrome, landing beyond the aerodrome, and conducting a turnback towards the aerodrome.

Stay in control

If nothing else, maintain glidespeed and plan a maximum bank angle against your personal minimums, which you will not exceed if a turnback is an option. Be prepared to re-assess the situation throughout any manoeuvre.